Abstract

In parallel with terrestrial and satellite wireless networks, a new alternative based on platforms located in the stratosphere has recently introduced, known as High Altitude Platforms (HAPS). HAPS are either airships or aircraft positioned between 17 and 22.5 km above the earth surface. It has capability to deliver a wide spectrum of applications to both mobile and fixed users over a broad coverage area. Wideband code division multiple access (WCDMA) has emerged as the mainstream air interface solution for 3G networks. Also the ITU has specifically authorized the use of some IMT-2000 (3G) frequency bands from HAPS. This project addresses only forward link power control for high altitude platform station for a WCDMA under the assumption of power control imperfections. Power control improves the uplink and the downlink performance both by equalizing the powers of all users in a cell and by compensating for the channel fading. However in real systems power control imperfections degrade the system capacity. In this project, the performance of two distance based forward link power control schemes (nth-power-of distance and optimum power control schemes) are evaluated for high altitude platform station (HAPS) W-CDMA systems. For a HAPs system with 19 beams, the total capacity of the system would be in the order of 1206 voice users or 144 data users. The coverage of the platform with 19 beams each with a radius of 1.2 km can by approximated by a circle with a radius of 6 km. It has been shown that HAPS UMTS gives capacity and resource management improvements